Practical Catalytic Cleavage of C(sp
<sup>3</sup>
)−C(sp
<sup>3</sup>
) Bonds in Amines
作者:Wu Li、Weiping Liu、David K. Leonard、Jabor Rabeah、Kathrin Junge、Angelika Brückner、Matthias Beller
DOI:10.1002/anie.201903019
日期:2019.7.29
The selective cleavage of thermodynamically stable C(sp3)−C(sp3) single bonds is rare compared to their ubiquitous formation. Herein, we describe a general methodology for such transformations using homogeneous copper‐based catalysts in the presence of air. The utility of this novel methodology is demonstrated for Cα−Cβ bond scission in >70 amines with excellent functional group tolerance. This transformation
Visible‐Light‐Mediated Aerobic Oxidative C(
<i>sp</i>
<sup>
<i>3</i>
</sup>
)−C(
<i>sp</i>
<sup>
<i>3</i>
</sup>
) Bond Cleavage of Morpholine Derivatives Using 4CzIPN as a Photocatalyst
作者:Chun‐Lin Dong、Lan‐Qian Huang、Zhi Guan、Chu‐Sheng Huang、Yan‐Hong He
DOI:10.1002/adsc.202100455
日期:2021.8.3
Herein, a metal-free strategy for the aerobic oxidative cleavage of the inert C(sp3)−C(sp3) bond was developed. Deconstruction of morpholine derivatives was conducted using visible light as an energy source and O2 as an oxidant under mild conditions. This procedure demonstrated suitable selectivity and functional group tolerance. Moreover, a possible mechanism involving a radical process was proposed
Aerobic iron-catalyzed site-selective C(sp3)–C(sp3) bond cleavage in N-heterocycles
作者:David K. Leonard、Wu Li、Nils Rockstroh、Kathrin Junge、Matthias Beller
DOI:10.1016/j.catcom.2021.106333
日期:2021.9
stability of C(sp3)–C(sp3) bonds makes the site-selective activation of these motifs a real synthetic challenge. In view of this, herein a site-selective method of C(sp3)–C(sp3) bond scission of amines, specifically morpholine and piperazine derivatives, using a cheap iron catalyst and air as a sustainableoxidant is reported. Furthermore, a statistical design of experiments (DoE) is used to evaluate
The reaction of primary aromatic amines with alkylene carbonates for the selective synthesis of bis-N-(2-hydroxy)alkylanilines: the catalytic effect of phosphonium-based ionic liquids
At T ≥ 140 °C, different primary aromatic amines (pX–C6H4NH2; X = H, OCH3, CH3, Cl) react with both ethylene- and propylene-carbonates to yield a chemoselective N-alkylation process: bis-N-(2-hydroxyalkyl)anilines [pX–C6H4N(CH2CH(R)OH)2; R = H, CH3] are the major products and the competitive formation of carbamates is substantially ruled out. At 140 °C, under solventless conditions, the model reaction of aniline with ethylene carbonate goes to completion by simply mixing stoichiometric amounts of the reagents. However, a class of phosphonium ionic liquids (PILs) such as tetraalkylphosphonium halides and tosylates turn out to be active organocatalysts for both aniline and other primary aromatic amines. A kinetic analysis monitored by 13C NMR spectroscopy, shows that bromide exchanged PILs are the most efficient systems, able to impart a more than 8-fold acceleration to the reaction. The reactions of propylene carbonate take place at a higher temperature than those of ethylene carbonate, and only in the presence of PIL catalysts. A mechanism based on the Lewis acidity of tetraalkylphosphonium cations and the nucleophilicity of halide anions has been proposed to account for both the reaction chemoselectivity and the function of the catalysts.
This invention relates to the reaction of aliphatic epoxides and primary amines to form hydroxymorpholines or morpholines by a process comprising reacting said epoxide and primary amine in the presence of a ruthenium-containing compound plus a tertiary phosphine.